This patch makes shrink_slab() with task's memcg in drop_slab_node(),
so we can free reclaimable slab objects belongs to memcg /lxc/i-vbe1u8o7
with following command:
cgexec -g memory:/lxc/i-vbe1u8o7 sysctl vm.drop_caches=2
Test with following steps:
root@i-yl0pwrt8:~# free -h
total used free shared buff/cache available
Mem: 62Gi 265Mi 62Gi 1.0Mi 290Mi 61Gi
Swap: 31Gi 0B 31Gi
root@i-yl0pwrt8:~# (cd /tmp && /root/generate_slab_cache)
root@i-yl0pwrt8:~# free -h
total used free shared buff/cache available
Mem: 62Gi 266Mi 60Gi 1.0Mi 2.2Gi 61Gi
Swap: 31Gi 0B 31Gi
root@i-yl0pwrt8:~# cgcreate -g memory:/lxc/i-vbe1u8o7
root@i-yl0pwrt8:~# cgexec -g memory:/lxc/i-vbe1u8o7 /root/generate_slab_cache
root@i-yl0pwrt8:~# free -h
total used free shared buff/cache available
Mem: 62Gi 267Mi 58Gi 1.0Mi 4.1Gi 61Gi
Swap: 31Gi 0B 31Gi
root@i-yl0pwrt8:~# cgexec -g memory:/lxc/i-vbe1u8o7 sysctl vm.drop_caches=2
vm.drop_caches = 2
root@i-yl0pwrt8:~# free -h
total used free shared buff/cache available
Mem: 62Gi 268Mi 60Gi 1.0Mi 2.2Gi 61Gi
Swap: 31Gi 0B 31Gi
root@i-yl0pwrt8:~# sysctl vm.drop_caches=2
vm.drop_caches = 2
root@i-yl0pwrt8:~# free -h
total used free shared buff/cache available
Mem: 62Gi 267Mi 62Gi 1.0Mi 290Mi 61Gi
Swap: 31Gi 0B 31Gi
Signed-off-by: Neil Sun <neilsun@xxxxxxxxxx>
---
mm/vmscan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 562e87cb..81d770a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -702,7 +702,7 @@ void drop_slab_node(int nid)
return;
freed = 0;
- memcg = mem_cgroup_iter(NULL, NULL, NULL);
+ memcg = mem_cgroup_from_task(current);
do {
freed += shrink_slab(GFP_KERNEL, nid, memcg, 0);
} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
--
2.7.4
